Slashdot videos: Now with more Slashdot!

View

Discuss

Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).

You do realize a Yellowstone eruption would be slightly larger than St. Helens was right?
"The Island Park Caldera supereruption that produced the Huckleberry Ridge Tuff was the largest and produced 2,500 times as much ash as the 1980 Mount St. Helens eruption."

The argument always seems to be how wildly unlikely it'll happen. The problem is we are due for an eruption and what is stopping it from happening now? Anyone ever hear of Mt St Helens or Krakatoa? The entire ring of fire has been more active in recent years than any time on record. Yellowstone is showing every sign of increased activity and there has been a lava dome rising from below for a number of years, exactly what happens before an eruption. The only thing alarmist was the 2/3 quote, never heard that one before. The quote I heard was 1/3 of the US would be affected directly. Possibly 2/3 would have ash falls but so would most of the world since the ash would reach the stratosphere. Denver is toast as well as any city within 500 miles with severe damage extending to 1000 miles or more. Millions would be lost in the first hours and millions more from starvation. It would affect the world climate for many years and ironically would reverse some of the global warming for a time. The world won't end but it will be devastating.

People should be concerned since it WILL erupt eventually. What are the odds of it erupting within the next 10 years? 50/50. Rediculous? look at it this way, it's showing every sign of an eruption and it's due for one. It either happens or it doesn't, 50/50. That's the God's honest truth. Any other statistic is pointless because they all assume it may never erupt. Once an event like this comes due it will happen whether it's tomorrow or in a thousand years. Is there a chance it'll be in a thousand years? Of coarse but the whole point no one will admit to is it's just as likely to be next year as in a 1000 years the odds are exactly the same.

No, it could very easily be
much, much worse [wyomingnews.com] than Mt St Helens.

The 1980 explosion at Mount St. Helens in Washington state blew out about 540 million tons of debris. Morrell said an explosion at Yellowstone likely would be 1,000 times greater, releasing about half a billion tons of ash.

Experts say such an event would have a colossal impact on a global scale...
It would have a similar effect to a 1.5km-diameter space rock striking Earth, they claim....
A super-eruption is also five to 10 times more likely to happen than an asteroid impact, the report claims....
The volcanic winter resulting from a super-eruption could last several years or decades, depending on the scale of an eruption, and according to recent computer models, could cause cooling on a global scale of 5-10C.... The crater from the last super-eruption, 640,000 years ago, is large enough to fit Tokyo - the world's biggest city - inside it.

Not just a dusting of ash, by any means. To extrapolate from a single event (Mt St Helens) which may or may not even be in the same geologic region (I don't know) is pointless when the Snake River Plain has erupted several times over - the entire landscape their bears the scars of it.

Um no, dude, you don't really get it. If Yellowstone blows, there is no volcano eruption in human history that even remotely comes close. Mt. St. Helens would look like a fart standing next to Chernobyl. Areas 400 miles away would get covered in a foot of ash. There is just nothing like it.

The number of deaths could be staggering. That foot of ash, even 400 miles away in Denver, would collapse most roofs, and any with people in them would get severely injured or die. It would be the end of the U.S. as a global superpower, and there would be wars. You are naive.

Fortunately, the Yellowstone volcanic system shows no signs that it is headed toward such an eruption in the near future. In fact, the probability of any such event occurring at Yellowstone within the next few thousand years is exceedingly low.

...

Lava flows and small volcanic eruptions occur only rarely--none in the past 70,000 years. Massive caldera-forming eruptions, though the most potentially devastating of Yellowstone's hazards, are extremely rare--only three have occurred in the past several million years. U.S. Geological Survey, University of Utah, and National Park Service scientists with the Yellowstone Volcano Observatory (YVO) see no evidence that another such cataclysmic eruption will occur at Yellowstone in the foreseeable future.

(emphasis mine)

As for that "several million years" figure for a devastating explosion of the kind TFA is describing, consider that the United States as a nation is still less than 250 years old. I'm not saying it can't happen, but the idea that "it hasn't happened in a long time so it must be ready to happen now" is just a popular Las Vegas delusion.

Yellowstone's largest eruption was 2,500 times more powerful than St. Helens.
It's eruptions cover hundreds [yellowstone.net] of square kilometers, not tens of thousands.
Most of the United States by area would see a few meters of ash, not a football field's worth (which would be plenty devestating enough).

Yay for mods blindly modding up posts that contain numbers as "informative."

Only problem with reducing the pressure is that the pressure is the only thing keeping it safe.

A magma chamber apparently has a stack of gasses etc under high pressure. While they're under high pressure they stay in solution, but as soon as the pressure is released, all the gasses come out of solution, rapidly expand and well... #NO CARRIER

Unfortunately we don't have firsthand data on what a very large caldera forming eruption looks like in its earliest stages.;-)

If we look at smaller eruptions elsewhere, such as Mt. Mazama in Oregon when it erupted to form Crater Lake, there's enough information to piece together a pretty good narrative. (Unfortunately I am not familiar with much research from Yellowstone documenting the geologic evidence for precursors to its climactic eruptions, although I am aware of the many smaller eruptions that preceded the big ones.)

At Crater Lake the narrative is a bit disconcerting in that it appears to have started off like any other bog standard plinian eruption, which is admittedly not a trifling event, but then as that eruption wound down and you might have expected the eruption to end, it was then that the caldera collapse began which unleashed the main show. The point is just because an eruption starts out small doesn't mean it will end that way -- especially in this kind of volcanic system where you have a good sized reservoir of fairly explosive silica rich magma. On the other hand, just because there's a small eruption it doesn't mean a large one is imminent.

Mt. Mazama was a large complex edifice built of countless prior eruptions, and even fairly large lava flows that erupted only shortly before the caldera forming event; a couple hundred years prior to the climactic eruption a very thick rhyodacite lava flow squeezed down the flank to form what we now call Llao Rock.

nah, it won't quite be that bad. most predictions expect the immediate danger zone to have a radius of 1000-1600km, with pumice & ash deposit probably covering all of California and most of the Midwest [tulane.edu]. but rather than being burned, most deaths/injuries will likely be caused by ash inhalation.

luckily, modern humans have the benefit of science and technology.given enough warning, most people within range of the volcanic explosion and subsequent lava/pyroclastic flow (70,000 to 100,000+ individuals by some estimates) can be evacuated beforehand. everyone else will simply have to stay in doors for a couple of days before they too can be evacuated outside of the ash cover area.

the USGS seems pretty confident that the YVO monitoring program will detect any premonitory indicators (such as emissions of magmatic gases) of any such impending disaster. and studies indicate that, if there is a volcanic eruption, it is not likely to be a caldera-forming supervolcanic eruption due to insufficient rhyolitic magma-storage to sustain such an event.

in the event that a caldera-forming eruption takes place, then yes the ash will probably circle the entire globe and lower the temperature in the lower atmosphere for a few years, and that can have a severe impact on the ecology of the planet. but it's certainly survivable. and the chances of such an event actually occurring is still statistically insignificant--contrary to what is often reported, are are not "overdue" for a supervolcanic eruption. (the mean interval between such eruptions is 710,000 years, not 600,000 years.)

No, pretty easy to tell. In the immediate short term, the global cooling effect of stratospheric ash is FAR stronger. Tambora caused the northern hemisphere to skip a summer in 1816 in case you forgot. Not that the Dalton minimum helped either. It took five years for global temperatures to return to normal after Krakatoa in 1883.

Which is still on the same order of magnitude as the original equation, but also means we don't have to worry about the mass of oxygen consumed by the burning, or the mass of the CO2 given off. (Thanks to the DoE for giving the Gross Heat of Combustion for cellulose products.)

Volcanic "ash" is not burning wood "ash". Volcanic ash is actually pulverized, powdered rock that only superficially resembles wood ash as it falls and collects on the ground. It's not the result of any burning process.

More recently Mt Pinatubo [realclimate.org] caused a small but measurable drop in global temprature. Several similar events occured in the 20th century, the mesurable effect lasts a few years at most.

Long term? - During the 20th century mankind's GHG emmissions dwarfed those from volcanos and I suspect our areosols [wikipedia.org] (soot,etc) over the same period have done more to keep a lid on warming than the ash from volcanos.

Unlike anthropogenic climate change there is nothing much we can do about a volcanos except get out of the way, the fact that humans exist at all demonstrates primates have managed to do that for millions of years. The industrial age has only been going in earnest for a couple of centuries but already it has caused the sixth great extinction.

small amounts of volcanic ash might only irritate your lungs, but if a supervolcanic eruption took place, it would likely throw up tremendous amounts (~1000 cubic miles) of tephra/pyroclast, the finest particles of which could circle the globe and remain suspended in the atmosphere for years. if you're immediately downwind from such an eruption, you'd be breathing in heavy amounts of what is essentially microscopic shards [uidaho.edu] of broken glass [usgs.gov] for weeks or months.

archaeological evidence has been uncovered showing that the mass deaths of plains animals [rense.com] 12 million years ago during a supervolcanic explosion at Yellowstone were due primarily to lung disease from volcanic ash inhalation. even many animals that survived the initial ashfall were still killed by the ash [google.com] stirred up by their own movements or wind.

Why? Really, I'm curious why we can't trigger smaller eruptions if we know a bigger one will eventually happen. I'm sure there are reasons it wouldn't work today, but are there reasons it couldn't ever?

Quality of information is the fundamental problem, coupled with the variability of real rocks.

[/self : puts on my formal "geologist" hat ; it is my job, though not this particular aspect of geology]

The area around Jellystone (and all volcanos) has a long and complex history ; particular rock units vary on a scale of centimetres to metres and larger, through bedding and faulting, to say nothing of the more subtle variations resulting from hydrothermal alteration. These variations in constitution and physical organisation of the materials lead to considerable (several orders of magnitude) variations in rock strength on quite small scales - metres, if not finer.

So, to accurately characterise the rock volume where you're intending to set off a small, controlled eruption, you need that scale of knowledge of the rock units in order to work out where you can safely set off that "small, controlled eruption", and indeed, how to set off that "small, controlled eruption".

Which is well and good - it gives us a goal of the approximate level of information that we need to plan and execute the "small, controlled eruption" plan. We'd need to characterise most of the immediate vicinity of the volcano that we're planning to "defuse" - for the Jellystone hotspot hmmm, on the order of 100km of land area to a depth of several km, say 300km^3 of rock with data at (say) 10cm spacing, and with density, triaxial strength and stiffness data, temperature, pressure, stress field (triaxial again), and a few other bytes of data. Lets say 20 bytes of data per station and around 300 x 10^9(km^3->m^3) x 1000 (data points per m^3) = 3 * 10^14 stations. So we're looking at on the order of 10^16 bytes of data for the core area, and I'd guess the same for surrounding areas at progressively decreasing data density to control for "edge effects" (I'm getting a bit hand-wavy here ; it shows!). Say 10^17 bytes of raw data and working / intermediate results. That's around 100 petabytes, or approximately 10 years worth of LHC data [wikipedia.org].

That's a serious chunk of computing power, but not incredible. It also allows us to put some sort of cost on the project - the LHC is costing on the order of 5 billion USD, so we're looking into the same sort of region of cost for working out what to do and how to do it. GIVEN that we've got the data to analyse. And that's where the problem lies.

To get the data that's necessary to do this modelling, we're going to need to measure those 20-odd bytes of data for those points, at something approaching that data density. Which we don't have techniques for. We can get some data points - for example I can measure the porosity, permeability and fluid pressure at centimetric scale in a borehole. The tools used are the MDT (if I'm working with Schlumberger equipment) or RCI (from Baker Atlas), but there are others. For measuring rock strengths... well, I could conceive of relevant tools, and I could conceive of using them at the same time as doing the pressure measurements. Getting the triaxial stress field is a deal more involved (since drilling the borehole induces a change in the stress field, by drilling out the rock), but I can envisage doing it. So let's say that we can get our data using currently conceivable direct measurements for essentially the cost of drilling the borehole.

A 3km hole in hard rock. That would be in the region of a million USD, if you're doing it wholesale. To characterise the whole rock volume, you're going to need to drill in the order of one every 10 metre to make even a faint approach at getting the areal data density (your surface borehole is going to be nearly a metre across, so you can't go to any better data density than 1/